| 摘要 |
PURPOSE:To perform recording under the same condition as that where the diameter of picture element is large and, at the same time, to optionally control the diameter of picture element, by forming an electrostatic image on a recording medium in the first place under the control of a control electrode and erasing a part of the image by means of an ion flow of the opposite polarity. CONSTITUTION:When a control electrode 5 consisting of parallel plate electrodes having a hole at the center and a recording medium 7 are put between a corotron 3 which has a corona line 1 and is a corona producing source and a facing electrode 4 and a forward electric field is applied across the control electrodes 5, an ion flow passes through the hole 6 and forms an electrostatic image on the recording medium 7. When an opposite electric field is applied across the electrodes 5, no electrostatic image is formed, because the ion flow cannot pass through the hole 6. On the other hand, when the voltage applied across the corona line 1 is made opposite in polarity and a forward electric field is applied across the electrodes 5, negative electric charges pass through the hole 6. When the opposite voltage is applied across the electrodes 5, the negative electric charges do not pass through the hole 6. When these cases are appropriately combined, a positive and negative ion flow can be irradiated upon the recording medium 7 optionally and an electrostatic image can be formed on the medium 7. |
